Process of manufacturing material for alkaline batteries.



' fully known,

WILLIAM MORRISONQOF DES MOINES, IOWA.

PROCESS OF MANUFACTURING MATERIAL FOR ALKALINE BATTERIES.

No Drawing.

Specification of Letters Patent.

Application filed September 26, 1910. Serial No. 583,896.

PatentedNov. 22, 19.1.0.

To all whom it may concern:

Be it known that I, WILLIAM MORRISON, a citizen of the United States ofAmerica, and resident of Des Moines, Polk county, Iowa, have invented acertain new and use-- ful Improvement in Processes of Manufac turingMaterial for an Alkaline Battery, of which the following is aspecification.

My invention relates to improvements in reversible galvanic batteries,in which zinc is one of the elements, and more particularly to a batteryin which the positive electrode is composed of a compound of zinc andchromium: e

It has for its object the improved method for making this compound forthe positive electrode.

A further object is the improved method by which an electrode of thiscomposition is constructed at moderate cost and has a longperiod ofefficiency.

These and such other objects as may hereinafter appear are attained bymy invention: My improved electrode is obtained in the followingmannerglfirst take a sufiicient quantity of chromium sulfate, such as can beurchasedon the market, the green colore compound I have found to bebetter for my purpose than any of the other chromium sulfate compoundsupon the market. I then thoroughly dissolve this compound in *hotdistilled water. Next I take asuflicient quantity of zinc oxid and mixthe same thoroughly in water, preferably by means of an agitator, untilthe solution is entirely free from lumps and a thin paste is obtained. Ithen add to this solution, while it is in an agitated condition, thechromium sulfate solution obtained above. The proportions of thechromium compound and thezinc oxid can be varied to quite a largedegree, but I find that good results are obtained by using three poundsof zinc oxid to one pound of the chromium sulfate. The chromium sulfatesolution, when firstadded to the zinc and, is a deep green. The actionof the zinc oxid upon this, however, produces 8, Hear solution andalight green preci itate of zinc ox'id and chromium sulfate. T e exactcomposition of this precipitate is not but it is thou ht that thechromium unites with both t e zinc oxid and the sulfuric acid, as it isfound that thesolution contains no zinc sulfate. However, the metchemical reactions which take place Icre Y ;,,;pot thought to essential,as my invention consists in the particular method which I employ inobtaining my final compound. I then pour off the solution from thisprecipitate of zinc oxid and chromium sulfate, and add a strong solutionof hot caustic potash.

This caustic potash acts to form a solution of potassium sulfate and aprecipitate-of a zinc chromium compound. If suitable proportions areused in the first place, this com pound may be zinc chromite; but whendifferent proportions are used, other compounds of zinc and chromiumwill be obtained. I, therefore, do not wish to limit myself to thecompound of zinc chromite. I then pour off the potassium sulfatesolution from this zinc chromium precipitate, and then wash thisprecipitate several times with hot water in order to remove all tracesof'the sulfate. The zinc chromite or other zinc chrom1um compound whichis obtained is then dried in any suitable manner, such as with' acentrifugal drier, and the material is then ready to be packed into thegrid.'

- \Vhile I have described my improvedmet hod of pr'oducin this zincchromium compound, I do not esire to be restricted to the specificmethod described, as various modifications will readily suggest,themselves. For example, other equivalent solutions may be used in placeof the caustic potash which I have described I do not .wish to limitmyself to the exact method described, as it is obvious that variousmotli fieations will readily suggest themselves to anyone skilled intheart.

The electrode thus obtained is preferably used with an alkalineelectrolyte, such as potassium hydroxid, and any suitable negativeelectrode may be obtained; for example, such a one application SerialNumber 531,230, in which an electrode composed of the oxids of silverand mercury is stood, however, that I do not desire to limit myself tothe use of any particular electro-' lyte or negative electrode, as alarge number of such electrolytes andnegatlve electrodes are adapted foruse w th myjrmproved positive electrode, consisting of a zinc chromiumcom-pound. Imay also produce as described in my co-pending described.It. is to be undermy compound of zinc and chromium by the followingmethod: To a suitable quantity of chromium sulfate orv other chromesalts add a hot strong solution of potassium hydrox'id.

An excess-of the hydro'xid should be used "so that the chromium is firstprecipi l tated will be redissolved. This solution is fate.

then added to the agitated zinc oxid whereby a precipitate-of a zincchromium compound is obtained and a solution. of potassium sul- Thisprecipitate is then Washed as before to remove all traces of the sulfateand then dried. Before packing the material in the grid a suitablequantity of mercury oxid,

- traces ofthe sulfate.

The method of producing a compound for use in reversible galvanicbatteries, which consists in adding -a solution of chromium sulfate to azinc oxid,-wherebya compound of zinc OXlCl and chromium sulfate isobtained, then acting upon this With' a strong alkaline solution toremove the sul fate, thus leaving a compound of zinc and chromium oxid,and then Washing this compound to remove traces of the sulfate.

3. The method-of. producing electrodes for reversible galvanicbatteries, which consists in adding to a quantity of zinc oxid achromium sulfate solution whereby a precipitate containing a compound ofzinc oxid and chromium sulfate is obtained, then addingto thisprecipitate an alkaline solution, in

then washing the precipitate thus. obtained 'in adding to a quantity ofzinc oxid a chromium'sulfato solution whereby a precipitate containing acompound of zinc oxid and chromium sulfate is obtained-then adding tothis precipitate an alkaline solution, and in then drying theprecipitate thus obtained and then par-king the sanie in a suitablegrid.

5. The method of producing a compound for use in i'nveisible galvanicbatteries, which consists of combining zinc oxid and chromium sulfate,in then adding to the precipitate thus obtained isolation of potassiumhydroxid, and then Washing this coniponnd to remove traces of'thesulfate.

6. The method of producing a compound for use in reversible galvanicbatteries, which consists of'combining zinc oxid and chromiumsulfate,.and in then adding to the precipitate thusobtained a solutionof potassium hydrokid,

7. The method of producing a compound for use in reversible galvanicbatteries, which consists in combining suitable quantitics of zinc oxid,chromium sulfate, and an alkaline solution from which is precipitated acompound containing zinc and chromium. Signed by me at (jhieago,Illinois, this 22d day of Sept. 1910.

, \VILLIAM MORRISON.

\Vitnesses:

ELLEN H. CLEGG, M. 1}. DuizNIoN.

